338 
MANUFACTURE OF TARTARIC ACID. 
which is found in the mother-liquors, resulting from the first ope- 
ration in the manufacture of cream of tartar, into bitartrate, espe- 
cially when the matters operated on have undeigone a commence- 
ment of fermentation. As, instead of water, these mother-liquors 
are employed in the solutions of fresh portions of the raw materials, 
they at length become charged with neutral tartrate of potash. 
To convert this neutral tartrate into bitartrate of potash, sulphuric 
acid is added until no further precipitation of bitartrate takes 
place : the mother-liquor contains, together with some bitartrate 
in solution, sulphate of potash, which serves in the before- 
mentioned process for converting tartrate of lime into bitartrate of 
potash. 
Manufacture of Tartaric Acid—The process indicated by the 
London Pharmacopoeia is not now adopted on the large scale ; the 
following is the process commercially employed. A large wooden 
vat or generator, as it is termed, closed at the top, and furnished 
with a man-hole secured by a water joint, is the apparatus or ves- 
sel used for the decomposition of the tartar and liberation of the 
tartaric acid. This generator is provided with an exit-pipe for 
the escape of the carbonic acid gas, liberated during the process, 
and an agitator or stirrer, consisting of a stout iron rod having 
attached to its lower extremity a long arm of wood to stir the 
contents of the generator, the upper extremity of the rod being 
connected by means of appropriate machinery with some motive 
power, as that of a steam engine. The generator is usually of a 
capacity of about 2000 gallons, and is larger at its base than at 
its summit. A pipe, in connection with a steam-boiler, enters at 
the side of the generator, and another pipe connected with a reser- 
voir of cold water, enters the upper part of the generator, which is 
also provided with cocks at suitable levels for the purpose of draw- 
ing off the contents. Into this generator, about one-fourth filled 
with water, 1500 pounds more or less (according to the quality of 
the tartar employed,) of whiting or washed chalk (carbonate of 
lime,) are introduced, steam is then allowed to blow in from the 
boiler so as to heat the water, and the agitator is set in motion 
until the lumps of the whiting are broken and a mass of uniform 
consistence obtained; this done, about two tons of tartar of ave- 
rage quality are introduced by degrees, and the agitator again set 
